Nitrogen and Phosphorus Derivatives

TABLE 10. Structural parameters of cyclopropylamine (121), 1-amino-1-methyl- (122) and 1-amino-1-phenylcyclopropane (123)  

A simultaneous crystallographic study (submitted for publication just a week later) gave essentially the same structure (Table 10). There are weak N—H- N hydrogen bonds of N- N 3.22 A in the crystal. 

TABLE 11. Structural parameters of cyclopropyl isocyanate (124) and isothiocyanate (125) and isocyanocyclopropane (126)  

The isocyano group has been found to be linear within 1° at the nitrogen atom in isocyanocyclopropane (126). The structure has been determined from the MW spectra with some assumptions (Table 11). There is little difference between distal and vicinal bonds the latter are slightly elongated compared to 1. 

---

Nitrogen and Phosphorus Derivatives of Bivalent Tin and Lead. Following the first syntheses of tin(ii)- and lead(ii)-nitrogen bonds in 1974, Zeldin has reported the preparation and properties of bis(dimethylamino)tin(n). The compound is a white crystalline solid which is dimeric in cyclohexane solution, but monomeric in the vapour. Variable-temperature n.m.r. studies in chlorobenzene solution indicate exchange of dimethylamino-groups between bridge and terminal positions of the dimer structure (77). With pyridine, a 1 1 adduct is formed alcohols and... 

Eutrophication potential (EP). Eutrophication is referred to as the pollution state of aquatic ecosystems where the overfertilisation of water and soil has turned into an increased growth of biomass. EP is calculated in kg based on a weighted sum of the emission of nitrogen and phosphorus derivatives such as N2, NOx, NH, P04, P and chemical oxygen demand (COD). The classification factors for EP are expressed as phosphates equivalents. 

Low-valent nitrogen and phosphorus compounds are used to remove hetero atoms from organic compounds. Important examples are the Wolff-Kishner type reduction of ketones to hydrocarbons (R.L. Augustine, 1968 D. Todd, 1948 R.O. Hutchins, 1973B) and Barton s olefin synthesis (p. 35) both using hydrazine derivatives. 

Phosphazene polymers can act as biomaterials in several different ways [401, 402,407]. What is important in the consideration of skeletal properties is that the -P=N- backbone can be considered as an extremely stable substrate when fluorinated alcohols [399,457] or phenoxy [172] substituents are used in the substitution process of the chlorine atoms of (NPCl2)n> but it becomes highly hydrolytically unstable when simple amino acid [464] or imidazole [405-407] derivatives are attached to the phosphorus. In this case, an extraordinary demolition reaction of the polymer chain takes place under mild hydrolytic conditions transforming skeletal nitrogen and phosphorus into ammonium salts and phosphates, respectively [405-407,464]. This opens wide perspectives in biomedical sciences for the utilization of these materials, for instance, as drug delivery systems [213,401,405,406,464] and bioerodible substrates [403,404]. 

Nitrogen- and phosphorus-containing ligands are mainly represented by amino- (d d [13,112]) and imino- (384 [13,517,699]) phosphines, cyanophosphine derivatives, for example 385 and 386 [112], and various nitrogen-containing N,P-heterocycles, for example 387 and 388 [511,517]. Interaction of 383 with Lewis acids leads mostly to P-coordinated structures, for example 389 [112] ... 

Fig. 3.4. Transfer of nitrogen and phosphorus between pea and barley plants in the presence or absence of arbuscular mycorrhizas (AM), and where peas shoots were removed, (a) Experimental design (b) Amount of transfer under the different circumstances. Derived from Johansen and Jensen (1996).

---